From 34b5b3e127be045e3fbe7b55ec39b6c881a574e1 Mon Sep 17 00:00:00 2001 From: schwarze Date: Sat, 10 Jul 2021 17:45:16 +0000 Subject: [PATCH] Fix a read buffer overrun in X509_CERT_AUX_print(3), which by implication also affects X509_print(3). The ASN1_STRING_get0_data(3) manual explitely cautions the reader that the data is not necessarily NUL-terminated, and the function X509_alias_set1(3) does not sanitize the data passed into it in any way either, so we must assume the alias->data field is merely a byte array and not necessarily a string in the sense of the C language. I found this bug while writing manual pages for these functions. OK tb@ As an aside, note that the function still produces incomplete and misleading results when the data contains a NUL byte in the middle and that error handling is consistently absent throughout, even though the function provides an "int" return value obviously intended to be 1 for success and 0 for failure, and even though this function is called by another function that also wants to return 1 for success and 0 for failure and even does so in many of its code paths, though not in others. But let's stay focussed. Many things would be nice to have in the wide wild world, but a buffer overflow must not be allowed to remain in our backyard. --- lib/libcrypto/asn1/t_x509a.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/lib/libcrypto/asn1/t_x509a.c b/lib/libcrypto/asn1/t_x509a.c index fd68211b849..b0346fa6813 100644 --- a/lib/libcrypto/asn1/t_x509a.c +++ b/lib/libcrypto/asn1/t_x509a.c @@ -1,4 +1,4 @@ -/* $OpenBSD: t_x509a.c,v 1.8 2014/07/11 08:44:47 jsing Exp $ */ +/* $OpenBSD: t_x509a.c,v 1.9 2021/07/10 17:45:16 schwarze Exp $ */ /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL * project 1999. */ @@ -105,8 +105,8 @@ X509_CERT_AUX_print(BIO *out, X509_CERT_AUX *aux, int indent) } else BIO_printf(out, "%*sNo Rejected Uses.\n", indent, ""); if (aux->alias) - BIO_printf(out, "%*sAlias: %s\n", indent, "", - aux->alias->data); + BIO_printf(out, "%*sAlias: %.*s\n", indent, "", + aux->alias->length, aux->alias->data); if (aux->keyid) { BIO_printf(out, "%*sKey Id: ", indent, ""); for (i = 0; i < aux->keyid->length; i++) -- 2.20.1